An electron micrograph of an Ebola virus virion

An electron micrograph of an Ebola virus virion.

Ebola has been making lots of news this year, as the virus has popped up in several West African countries. We are in the midst of the largest and most widespread outbreak in history.

Fruit bats are the main carriers of the virus in nature. Initially, humans become infected with the ebola virus after contact with infected bats or any living or dead animals that have been infected by the bats. This contact is often thought to be from consumption of infected meat. After humans become infected, the disease spreads through contact with infected bodily fluids including sweat, saliva, urine and semen. Ebola is insidious, and in some cases can take up to 21 days after exposure before symptoms manifest. Symptoms include a sudden onset of flu-like fever, ache and fatigue followed by vomiting or diarrhea.

Sky News details why the virus is so deadly:

When ebola enters the body, it targets dendritic cells in the immune system.

Normally, when a virus is detected, these cells tell other cells to produce antibodies.

Ebola prevents that signal getting out. As far as the immune system knows, everything inside the body is fine.

Left alone, ebola then begins replicating rapidly. It then spreads into the bloodstream, infecting the whole body. Cells start to break up and die, in huge numbers. That finally triggers the immune system, which kicks in – far too aggressively.

Ordinarily when you get sick, the body releases proteins called cytokines. Some of these cells tell your blood vessels to become more permeable. This is to let antibodies travel through the body more quickly to fight the disease.

But once ebola has taken hold of your body, the immune system reacts much too aggressively – and launches a cytokine storm.

This causes blood vessels to become far too permeable, and they leak. At the same time, the body’s blood clotting mechanisms also act abnormally.

This causes internal and external bleeding and is why ebola is known as a haemorrhagic fever. It causes tissue damage and organ failure.

Though the disease is deadly, people do survive and countries can contain outbreaks. Survivors’ blood may contain antibodies that can be used to treat others suffering from the disease.

2014 nobel prizes


The Nobel prizes were awarded this week. Each year there are three science related awards in the fields of medicine, physics and chemistry.

In the field of medicine, the award went to John O´Keefe, May-Britt Moser and Edvard I. Moser for discovering the brain cells that make up our positioning system. In 1971 John O’Keefe discovered that when a rat was in a certain part of the room, one part of the hippocampus was always activated. When the rat was in other parts of a room there were different cells activated. He termed these cells “place cells” and determined that they formed a map. In 2005, the Mosers discovered what they called “grid cells”. These cells generated a coordinate system and aid in finding our way along paths. Read more about the physiology and medicine prize here.

This years physics medal went to the invention of LEDs and was awarded to Isamu Akasaki, Hiroshi Amano, and Shuji Nakamura. The three researchers contributed to the development of LED technology, which is prevalent in today’s telephones, lamps, and computers. LED lights emit brighter light than incandescent lights and for longer periods of time. Read more about the award at Scientific American. The press release is here.

The chemistry prize was awarded to Eric Betzig, Stefan Hell, and William Moerner for developing super resolved fluorescence microscopy. Researchers thought they were limited by the limit of diffraction when it came to resolving images under a microscope. The three Nobel recipients have developed technology that helped overcome this limitation and resolve images into the nanometer scale. Stefan Hell developed a technique called stimulated emission depletion microscopy or STED. Bezig and Moerner, working separately, performed the groundwork for the development of single molecule microscopy. You can read the press release here, and a more detailed description of high resolution microscopy here.

the warmest year on record?

Aug 2014 Climate Deviations

NOAA’s data indicate that temperatures were above historical norms in August across most of the globe.

2014 is shaping up to be the warmest year on record. Surprising to hear for us East Coasters, who enjoyed a mild summer. From Scientific American:

“If we continue a consistent departure from average for the rest of 2014, we will edge out 2010 as the warmest year on record,” said Jake Crouch, a climatologist with NOAA’sNational Climatic Data Center, during a press briefing Thursday.

“If we continue a consistent departure from average for the rest of 2014, we will edge out 2010 as the warmest year on record,” said Jake Crouch, a climatologist with NOAA’sNational Climatic Data Center, during a press briefing Thursday.

The NOAA report comes on the heels of NASA’s temperature data showed that August was the warmest August ever.

the science of autumn


As we get ready for the splendor of fall foliage, Compound Interest explains the science of autumn leaves with his signature infographics:

Carotenoids and flavonoids are both large families of chemical compounds. These compounds are present in the leaves along with chlorophyll, but the high levels of chlorophyll present in the summer months usually masks their colours. As the chlorophyll degrades and disappears in autumn, their colours become more noticeable – both families of compounds contribute yellows, whilst carotenoids also contribute oranges and reds.

Check the link for the graphic and more detail.

do gut bacteria prevent allergies?

Intestinal tracts of germ free mice and mice given clostridia bacteria. The higher levels of mucus in the clostria tracts is thought to prevent allergens from leaking into the bloodstream.

Science News brings word of a recent PNAS report on gut bacteria and allergies. In the study, researchers gave a group of mice antibiotics to wipe out their gut microbiome. Feeding the mice peanuts after this treatment seemed to induce allergy-like responses, that weren’t observed in mice who didn’t receive the treatment. The researchers gave the mice Clostridia bacteria to replenish the microbiome, and the response diminished.

Cathryn Nagler of the University of Chicago and colleagues treated some mice with antibiotics to wipe out the animals’ gut bacteria, and then triggered an allergy-like response to peanut particles. Peanuts revved up the germ-free animals’ immune systems — but mice with normal gut bacteria didn’t have the bad reaction.

Giving germ-free mice a dose of Clostridia bacteria made the animals more like their counterparts with normal gut flora. The microbes encourage mouse cells to make mucus that helps seal up the intestines, keeping food particles from slipping into the bloodstream and riling up the immune system, the researchers found.

The researchers suggest that this might also hold true for humans.

carbs fuel colon cancer in mice

Carbohydrate rich diets, especially refined carbohydrates, have been linked to higher rates of colon cancer in the developed world, when compared to developing nations. A new report in the journal Cell provides insight into how this might come to be. Science News explains:

To probe the link between colon tumors and gut microbes, the researchers treated mice engineered to be prone to colon cancer with antibiotics. By eradicating intestinal bacteria, the drugs hindered malignant lumps of cells called polyps from growing in the lining of the colon and small intestines. The team then noticed that feeding the rodents a diet low in sugar and starch also reduced the growth of polyps.

The mice had two gene mutations often linked to colon cancer in people,one of which derails a cell’s ability to fix errors that arise during DNA replication, known as the mismatch DNA repair system.

A mismatch repair deficiency causes cells in the lining of the colon to divide quickly, explains study leader Alberto Martin, an immunologist at the University of Toronto. Bacteria and carbs speed the process, he says, damaging the genome and leading to tumor growth.

The researchers surmised that when microbes feast on carbohydrates, the germs must produce a chemical that pushes colon cells lacking the ability to repair DNA mismatches toward uncontrollably multiplying into tumors.

The researchers discovered that gut bacteria process carbohydrates into butyrate, which can induce cancer in  APCMin/+MSH2−/− mice by allowing cancerous  MSH2−/−cells to proliferate uncontrollably in the colon.